The invention basically concerns a process for supervising and/or controlling of physical treatment processes and bioreactions in ventilation systems, preferably during granulating, instantizing, dragee making and film coating processes. The invention is also concerned with bioreaction and drying processes, in which inlet air or gas is fed in and exhaust air or gas let out, whereby at least the humidity of the exhaust air is measured.
For supervising such processes in the prior art, auxiliary or indirect values, such as the motion of the goods to be treated and/or the temperature, were measured and a change of the treatment process was planned, if necessary, based on these values. However, these indirect measurements can result in measuring errors.
It is also already known to measure the humidity of the exhaust air and possibly of the inlet air in drying processes during their final phase, where there are only slight changes in humidity per unit of time. However, measurement of the actual humidity charging of the air or the product during the treatment process is not possible using this technique.
Furthermore, a measuring device with two electrodes is known, with which the conductivity of the goods to be treated is measured during a coating process. Such a technique also permits conclusions about the degree of humidity in the goods being processed, especially about the amount of liquid bonding agent. In addition, it is proposed here that a temperature measuring probe is to register the degree of drying during a subsequent drying process. Apart from the contamination resulting from the direct contact by the measuring probe reaching into the treated goods, the technique presents further problems in that the measuring of the desired data takes place through several transmissions so that there is an increased possibility for errors in the result. In addition, during a change of charges, especially during a change to another type of goods to be treated, the change-over, calibration, etc., of the measuring instruments creates further problems.
Similar disadvantages exist also in humidity measuring processes using an infrared measuring technique. Conclusions about the existing moisture in the goods treated are drawn from reflexes on a surface water film, which can also have additional disadvantageous influences when there is high humidity in the air surrounding the treated goods.